This study will evaluate an HBV vaccination program as a model for future HIV vaccine efficacy trials in a community-based study of drug users. Two components will be analyzed in an effort to increase vaccine acceptance adherence - behavioral intervention & an accelerated vaccine schedule. The study also will examine the effect of these variables on risk behaviors and incidence of HIV, HBV, & HCV infections. To accomplish these objectives, we propose a randomized behavioral intervention field trial. We will enroll 1600 current cocaine or heroin users negative for HBV & HIV markers from two closely matched, low-income, high drug endemic communities in Houston. All participants will be offered HBV vaccination and follow-up viral testing. One community will be randomly assigned to receive an outreach behavioral intervention designed to increase vaccine awareness and vaccine compliance. The other community will receive standard care. Participants electing to be vaccinated will be randomized to either a 0,1,6 month or a 0,1,2, month vaccine schedule. Groups will be followed for two years to determine rates of HBV vaccine acceptance/adherence to the 3-dose protocol. We also will measure any changes in risk behaviors & incidence of HIV/HBV/HCV infections as well as HBV vaccine immune response, if vaccinated. Drug users are the largest group of newly diagnosed HIV cases and so creating a model for an HIV vaccine's acceptance and adherence in this population is an important public health goal. There is little information about the acceptance/adherence to HBV vaccine use in the drug user population and while community-based outreach has been shown to be effective in reducing risk behaviors among not-in-treatment drug users, there is limited information about the utility of this approach and its effectiveness in increasing acceptance/adherence for a 3 dose vaccination protocol. This study will serve as a model for future HIV vaccine trials and will provide information on the effectiveness of outreach programs for increasing immunization among drug users. Unless an effective model based upon empirical experience is developed, any attempt to implement a HIV vaccination program among drug users is likely to be frustrated. If HBV vaccination coupled with outreach intervention can reduce risk behaviors and decrease the incidence of HIV/HCV infection, then this study will have a tremendous impact on the current HBV/HIV/HCV prevention strategy.